Method and apparatus for repairing a coke oven

ABSTRACT

A repairing method using a lance for repairing an oven wall surface of a coke oven comprises the steps of arranging a distance sensor at a top end of the lance, quantitatively measuring a depth of a worn or a damaged area by the distance sensor, and blowing a repairing material from a repairing nozzle to the worn area in accordance with a measurement result to thereby repair the worn area. The lance used in this repairing method has a multistage structure having a polygonal cross section and is extendable. With this structure, the oven wall surface can be scanned in a linear fashion or along a plane. If the top end of the lance is movable in accordance with a basic motion pattern and/or a travelling pattern, it is possible to readily repair a repair range having a complicated shape.

TECHNICAL FIELD

This invention relates to a method and an apparatus for repairing adamaged area of an oven wall which partitions a coke oven chamber(namely, a carbonization chamber) and a combustion chamber in a cokeoven of a chamber oven type.

BACKGROUND ART

A coke oven of a chamber oven type comprises regenerator chamberslocated at a lower portion of a furnace body. On the regeneratorchambers, coke oven chambers and combustion chambers are alternatelyarranged. Fuel gas and air are preheated (in case of rich gas, air aloneis preheated) in the regenerator chambers, burnt, then subjected to heatrecovery in the adjacent regenerator chambers, and discharged throughflue ducts. Coal charge in each coke oven chamber is indirectly heatedthrough oven walls from the combustion chambers located at both sidesthereof and is thereby subjected to dry distillation to be transformedinto coke. The coke oven of a chamber oven type is constructed mainly bysilica bricks and clay bricks and partly by heat insulating bricks andcommon bricks.

When the coke oven of a chamber oven type is used for a long period oftime, damages are inevitably caused to occur on oven walls due tovarious factors such as external mechanical force, thermal stress, andmoisture in coal charge. In particular, the oven walls in the coke ovenchambers are readily subjected to damages such as crack of joint,crevasse, flaking of bricks because those actions based on theabove-mentioned various factors are concentrated thereto. In presence ofsuch damages, resultant gas produced in the coke oven chamber may flowinto the combustion chambers. This results in environmental pollution byblack smoke produced in incomplete combustion and in deterioration ofproductivity due to local decrease in temperature of the combustionchambers. In view of the above, it has been a practice to spray mortaronto a damaged area as a repairing material. In case of a seriousdamage, the bricks must be exchanged at a high repairing cost.

It has been said that the coke oven of a chamber oven type has alifetime between 20 and 25 years. Recently, an extended lifetime between30 and 35 years is expected by an adaptive repair work enabled by animproved accuracy in diagnosing the damaged area of the oven wall and animproved repairing method.

On the other hand, replacement of the coke oven requires a largeinvestment of at least several tens of billions for each coke ovenbattery. This imposes a heavy pressure upon a financial environment of acompany. It is assumed that the existing coke ovens in this country havea lifetime of 35 years. In this event, most of those ovens must bereplaced around 2000 A.D. This implies a problem of shortage of silicabricks and oven constructors.

Taking the above into consideration, it is an urgent demand of the cokemanufacturers to create a universal and effective repairing techniquewhich prolongs the lifetime of the coke ovens of a chamber oven type upto 40 through 45 years or more.

As a method of repairing an oven wall of a coke oven, variousconventional methods are known as will presently be described. Asdisclosed in JP-A No. 206681/1983, a first repairing method uses a lanceunit provided at its top end with an optical system including an opticalfiber and comprises the steps of inserting the lance unit into a cokeoven chamber or a combustion chamber of a coke oven, scanning an ovenwall in relation to an absolute position on the oven wall to obtain animage of the oven wall, observing, via the image thus obtained, the ovenwall in the coke oven chamber or the combustion chamber to detect adamaged area, and memorizing image data of the oven wall in a memory ofa computer together with the absolute position on the oven wall.

As disclosed in JP-B2 No. 17277/1993, a second repairing method uses aheat-resistant protector tube provided with an optical system includingan optical fiber or a television camera, and comprises the steps ofinserting the protector tube into a coke oven chamber or a combustionchamber, detecting from the outside of the oven a damaged area of anoven wall in the coke oven chamber or the combustion chamber, andspraying a repairing material onto the damaged area of the oven wallfrom a repairing material spraying nozzle arranged in the protector tubeto thereby repair the damaged area.

As disclosed in JP-A No. 17689/1985, a third repairing method comprisesthe steps of adjusting a location of a flame spraying gun towards adamaged area of an oven wall by the use of a television camera and amonitoring unit, measuring a distance from the oven wall and the damagedarea thereof to the flame spraying gun, and carrying out repair workwith the distance controlled to be kept at a predetermined optimumdistance.

On the other hand, as an oven wall repairing apparatus, variousapparatuses are known as will presently be described. A first repairingapparatus is disclosed in JP-U No. 36703/1977. The first repairingapparatus comprises a water-cooled elongated cylindrical membercontaining supply pipes for combustible gas, oxygen, and refractorypowder. The elongated cylindrical member has one end provided with aflame spraying burner removably attached thereto and the other endprovided with a manipulation handle. The elongated cylindrical member isfitted to a support frame to be rollable and is mounted on a mobilecarriage to be movable and swingable.

A second repairing apparatus is disclosed in JP-A No. 17689/1985described in conjunction with the above-mentioned third repairingmethod. This repairing apparatus comprises a head portion to be insertedinto an oven. The head portion comprises a cooling case containing aflame spraying gun for spraying a monolithic refractory onto a damagedarea of an oven wall, a television camera for picking up an image of thedamaged area of the oven wall, and a range finder for measuring adistance from the oven wall and the damaged area thereof to the flamespraying gun. The second repairing apparatus further comprises amonitoring unit for enabling the image picked up by the televisioncamera to be observed at the outside of the oven. The head portion ismoved along three axes with reference to a measurement value obtained bythe range finder to control the distance from the oven wall and thedamaged area thereof to the flame spraying gun so that the distance iscoincident with an optimum distance.

As disclosed in JP-A No. 99592/1990, a third repairing apparatuscomprises a water-cooled box removably attached to a top end of a boom.The box contains those components required in flame spraying, such as aflame spraying burner and a monitoring camera.

As disclosed in JP-A No. 99589/1990, a fourth repairing apparatuscomprises a water-cooled box containing a monitoring camera and a flamespraying burner. This box is removably attached to an elongated beam.The elongated beam is attached to a carriage. The carriage has wheelsrunning along a track on a work floor. It is possible to swing andupwardly and downwardly move a support frame for supporting theelongated beam and to freely select forward or backward movement of thecarriage as well as an inclination angle of the elongated beam.

As disclosed in JP-A No. 32690/1992, a fifth repairing apparatuscomprises a running carriage. On the running carriage, a base is mountedto be movable up and down and swingable. A guide rail is tiltably formedon the base. A lance holder is movable along the guide rail. A flamespraying lance is telescopically fitted in the lance holder. A camerafor monitoring an oven wall is mounted on the lance holder.

According to the first and the second repairing methods described above,however, a wear condition of the oven wall is only visually detected anda wear amount, for example, a depression amount can not bequantitatively detected. In this connection, a sense of an operator isresorted to in determining a range to be repaired and the amount of therepairing material to be sprayed. In order to make the memory of thecomputer memorize all the image data obtained by the optical system, thememory capacity must be extremely large. In addition, the operator cannot enter into the oven because the repair work is carried out beforethe inside of the oven is completely cooled down. Besides, the opticalsystem is substantially useless during the repair work because of dust,smoke, and high-temperature flame produced by spraying the repairingmaterial. In this situation, the sense of the operator is substantiallyexclusively relied upon to carry out the repair work. Furthermore, thelance unit used in examining and repairing the oven wall in the cokeoven comprises a plurality of stages of lances in a telescopicarrangement. The lance at each stage comprises a cylindrical memberhaving a circular section and is therefore difficult to drive a rotationthereof. Specifically, when the first-stage lance is rotated around anaxis, slip is caused between contact surfaces of the first-stage lanceand the second-stage lance. In this event, the rotation of thefirst-stage lance is not transmitted to the second-stage lance.

According to the third repairing method described above, the distancebetween the flame spraying gun and the damaged area of the oven wall isadjusted to an optimum value to thereby reduce a rebound loss of thespraying material. Thus, a deposit efficiency of the spraying materialis improved. However, it is impossible to carry out optimum repair workin correspondence to the depth of the damaged area of the oven wall.

On the other hand, the above-mentioned first repairing apparatusrequires the operator to manipulate the manipulation handle with hiseyes watching the damaged area of the oven wall so as to repair thedamaged area by the use of the flame spraying burner located at one endof the water-cooled elongated cylindrical member. As a consequence, thesense of the operator is resorted to in determining the range to berepaired and the amount of the repairing material to be sprayed.

With the above-mentioned second repairing apparatus, the distancebetween the damaged area of the oven wall and the flame spraying gun canbe kept constant. However, no disclosure is made about quantitativedetection of a damage condition of the damaged area of the oven wall andexecution of the repair work adapted to the damage condition.

The third and the fourth repairing apparatuses described above requirethe operator to manipulate the boom or the elongated beam containing theflame spraying burner while monitoring the image of the oven wall asobtained by the monitoring camera. In this connection, the sense of theoperator is resorted to in determining the range to be repaired and theamount of the repairing material to be sprayed.

Like the above-described fourth repairing apparatus, the above-mentionedfifth repairing apparatus requires the operator to manipulate the flamespraying lance while monitoring the image obtained by the monitoringcamera. As a consequence, the sense of the operator is resorted to indetermining the range to be repaired and the amount of the repairingmaterial to be sprayed.

At any rate, according to the conventional repairing apparatuses and theconventional repairing methods, the damaged or the worn area is repairedin dependence upon a flat image of the surface of the oven wall.However, it is found out practically difficult to quantitatively detectthe depth of the damaged or the worn area from such a flat image. Takinginto account that the repair work is carried out in the coke oven at ahigh temperature and in a condition where visual observation isextremely difficult, it is even difficult to visually identify thedamaged or the worn area from the flat image alone.

It is therefore an object of this invention to provide a repairingmethod and a repairing apparatus for repairing an oven wall of a cokeoven, which remove the disadvantages in the conventional examiningmethods, repairing methods, and repairing apparatuses for an oven wallof a coke oven and which can quantitatively detect a wear condition anda wear amount of the oven wall.

It is an object of this invention to provide a repairing method and arepairing apparatus which are capable of repairing an oven wall even ata high temperature and in a severe condition.

DISCLOSURE OF THE INVENTION

In order to achieve the above-mentioned objects, the present inventorsrepeatedly executed various tests and accumulated their study. As aconsequence, it has been found out that automatic repair is enabled byexecuting the following steps. At first, a distance sensor located at atop end of a lance measures a distance between the top end of the lanceand an oven wall to obtain wear amount data of the oven wall. In thiscase, the top end of the lance having an injection nozzle for injectinga repairing material may be provided with an image pickup device such asa television camera or a fiber scope so that the oven wall is scanned bythe image pickup device to identify a damaged or a worn area. Inaddition, from a driving amount of a lance driving system for drivingthe lance, a position coordinate of the damaged area of the oven wall iscalculated with respect to the top end of the lance.

Next, with reference to the position coordinate of the damaged area ofthe oven wall and the wear amount data, a repair range as required isindicated and a predetermined repair pattern is selected. The lancedriving system is controlled to move the top end of the lance and tospray the repairing material onto the damaged area so as to repair thedamaged area.

Specifically, according to this invention, a method of repairing an ovenwall of a coke oven by the use of a lance is characterized by the stepsof mounting a distance sensor at a top end of the lance, measuring thedepth of a worn or a damaged area in the oven wall by the distancesensor, and injecting a repairing material from a repairing nozzlemounted at the top end of the lance onto the worn area to thereby repairthe worn area.

According to this invention, there is provided a method of repairing anoven wall of a coke oven by the use of a repairing apparatus which iscapable of mechanically or electrically controlling a position of arepairing nozzle, the method comprising the steps of preliminarilysetting, in a lance controlling section, basic motion patterns for therepairing nozzle and travelling patterns within a repair range,determining the repair range prior to start of repair work withreference to wear information of a worn or a damaged area, selecting arepair pattern comprising a combination of one of the basic motionpatterns for the repairing nozzle and one of the travelling patterns,and controlling a travelling speed of the repairing nozzle and/or anamount of a repairing material to be injected so that the damaged areais automatically repaired.

According to this invention, there is also provided a method ofrepairing a coke oven by the use of a repairing apparatus which iscapable of mechanically or electrically controlling a position of arepairing nozzle, the method comprising the steps of preliminarilysetting, in a lance controlling section, basic motion patterns for therepairing nozzle and travelling patterns within a repair range,preparing a wear distribution chart with reference to wear informationof a worn or a damaged area, determining the repair range with referenceto the wear distribution chart, selecting a repair pattern comprising acombination of one of the basic motion patterns for the repairing nozzleand one of the travelling patterns, and controlling a travelling speedof the repairing nozzle and/or an amount of a repairing material to beinjected so that the damaged area is automatically repaired.

According to this invention, there is also provided a method ofrepairing a coke oven by the use of a repairing apparatus which iscapable of mechanically or electrically controlling a position of arepairing nozzle, the method comprising the steps of preliminarilysetting, in a lance controlling section, basic motion patterns for therepairing nozzle and travelling patterns within a repair range,determining, prior to start of repair work, the repair range withreference to wear condition of a worn or a damaged area, setting adistance between a distance sensor and a normal brick surface around theworn area at the time instant of measurement of wear, selecting a repairpattern comprising a combination of one of the basic motion patterns forthe repairing nozzle and one of the travelling patterns, controlling atravelling speed of the repairing nozzle and/or an amount of a repairingmaterial to be injected, measuring a distance between the distancesensor and a repair surface varying from time to time, calculating adistance between a measurement position of the distance sensor at thetime instant of measurement of a damage and a repair position of thedistance sensor during the repair work, and monitoring that the repairsurface varying from time to time exceeds a virtual normal brick surfacein the worn area.

According to this invention, there is also provided a method ofrepairing a coke oven, comprising the steps of scanning an oven wallsurface by the use of an image pickup device mounted at a top end of alance having a repairing nozzle for injecting a repairing material,displaying an image on a monitor, measuring a distance between the topend of the lance and the oven wall surface by a distance sensor mountedat the top end of the lance to obtain wear amount data of the oven wallsurface, calculating, from a driving amount of a lance driving mechanismfor driving the lance, position coordinate data of a worn or a damagedarea in the oven wall surface with respect to the top end of the lance,indicating a required repair range on the oven wall surface andselecting a repair pattern with reference to image information of thewall surface, the wear amount data, and the position coordinate data ofthe worn area, and repairing the worn area in the oven wall surface byspraying in accordance with the repair pattern as selected.

According to this invention, an apparatus for repairing a coke ovencomprises a multistage telescopic lance unit provided at its top endwith a repairing nozzle which is for injecting a repairing material andwhich is movable along a plane, a lance driving mechanism for drivingthe multistage telescopic lance unit, a distance sensor mounted at thetop end of the multistage telescopic lance unit to be adjacent to thenozzle for measuring a distance from an oven wall surface, and a lanceoperating section for calculating wear amount data of the oven wallsurface in response to a signal supplied from the distance sensor andfor operating the lance unit with reference to the wear amount data andposition coordinate data of a worn or a damaged area so that the nozzleis moved on the worn area in the oven wall surface.

According to this invention, an apparatus for repairing a coke oven bythe use of a multistage telescopic lance unit comprises the multistagetelescopic lance unit having an axis extendable in a predetermineddirection and a lance driving system for driving the multistagetelescopic lance unit, the multistage telescopic lance unit comprising afirst-stage lance, second-stage through N-th-stage lances assembled inthe first-stage lance to be extendable in an axial direction, and afixed outer cylinder for fitting and accommodating the first-stage lancetherein to thereby support the first-stage through the N-th-stagelances, the lance driving system comprising a lance extension drivingmechanism formed between the fixed outer cylinder and the first-stagethrough the N-th-stage lances, and a tilting mechanism for tilting thefixed outer cylinder in a vertical plane.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a multistage telescopic lance unit foruse in a repairing apparatus for a coke oven according to thisinvention.

FIG. 2 is a side view for describing a tilting mechanism of themultistage telescopic lance unit illustrated in FIG. 1.

FIG. 3 is a plan view for describing a swinging mechanism of themultistage telescopic lance unit illustrated in FIG. 1.

FIG. 4 is a transversal sectional view illustrating a structure of a topend of the multistage telescopic lance unit illustrated in FIG. 1.

FIG. 5 is a schematic diagram for describing a light shielding filterswitching unit located in front of an image pickup device mounted at thetop end of the multistage telescopic lance unit illustrated in FIG. 4.

FIG. 6 is a schematic lateral sectional view illustrating an extensiondriving mechanism of the multistage telescopic lance unit illustrated inFIG. 1.

FIG. 7 is a schematic horizontal sectional view illustrating anarrangement of rollers in the extension driving mechanism of themultistage telescopic lance unit illustrated in FIG. 1.

FIG. 8 is a longitudinal sectional view of a first example of themultistage telescopic lance unit, taken along a line A--A in FIG. 7.

FIG. 9 is a longitudinal sectional view of a second example of themultistage telescopic lance unit, taken along a line A--A in FIG. 7.

FIG. 10 is a longitudinal sectional view of a third example of themultistage telescopic lance unit, taken along a line A--A in FIG. 7.

FIG. 11 is a view for describing an operation of arranging a lancecarriage of the repairing apparatus in parallel to a front side of theoven.

FIG. 12 is a view for describing an operation of positioning themultistage telescopic lance unit at the center of the oven.

FIG. 13 is a flow chart for describing the operation of arranging thelance carriage in parallel as illustrated in FIG. 11.

FIG. 14 is a flow chart for describing the operation of positioning themultistage telescopic lance unit at the center of the oven asillustrated in FIG. 12.

FIGS. 15(a)-15(c) are for describing modifications of the placement ofan injection nozzle mounted at the top end of the multistage telescopiclance unit.

FIG. 16 is a block diagram illustrating a processing section in therepairing apparatus according to this invention with a signal processingcontrol section at its center.

FIG. 17 shows an image of an oven wall in a restricted range as obtainedby the repairing apparatus according to this invention.

FIG. 18 shows an image of the oven wall in a relatively wide range asobtained by a wide-range camera used in the repairing apparatusaccording to this invention.

FIG. 19 shows an image representative of observation data of a weardistribution chart of a damaged area as prepared according to thisinvention.

FIG. 20 shows an image of one example of a repair range and a repairpattern used in this invention.

FIG. 21 is a view for describing an operation of preventing protrusionof a spraying material by the use of a second method according to thisinvention.

FIGS. 22(a)-22(d) show basic motion patterns for the injection nozzle ofthe repairing apparatus according to this invention.

FIGS. 23(a)-23(f) show basic travelling patterns of the injection nozzlewithin the repair range.

FIG. 24 shows a travelling pattern of the injection nozzle in case wherethe oven wall is repaired by the second method according to thisinvention.

FIGS. 25(a)-25(c) show a relationship of a wear condition of the ovenwall, a travelling pattern of the injection nozzle, and a travellingspeed of the injection nozzle.

FIGS. 26(a)-26(c) show a relationship of the wear condition of the ovenwall, the travelling pattern of the injection nozzle, and an amount ofthe spraying material to be sprayed.

FIGS. 27(a)-27(c) are a view for describing a method of repairing a deeprepair part from a deeper level to a shallow level.

FIG. 28 is a view for describing a method of keeping a distance betweenthe injection nozzle and the oven wall surface constant incorrespondence to the depth of a worn or a damaged area.

FIG. 29 is a view for describing an operation of restarting automaticrepair which has temporarily been interrupted in the middle of therepair work according to a selected repair pattern.

MODE FOR EMBODYING THE INVENTION

Now, description will be made as regards embodiments of this invention.FIGS. 1 through 3 show a repairing apparatus according to this inventionwhich comprises a multistage telescopic lance unit as seen from thefigures. At first, FIG. 1 shows an orthogonal coordinate system havingan X axis along a horizontal plane, a Y axis perpendicular to thehorizontal plane, and a Z axis perpendicular to a plane defined by the Xaxis and the Y axis. Herein, the repairing apparatus according to thisinvention will be outlined in conjunction with the orthogonal coordinatesystem. The repairing apparatus is located so that the plane defined bythe X axis and the Y axis is parallel to an oven wall surface of a cokeoven. In this state, the repairing apparatus is movable on the plane ina linear fashion or in a two-dimensional fashion. Upon completion ofrepair, the repairing apparatus can be moved along the Z axis to beguided into another coke oven.

The repairing apparatus illustrated in FIG. 1 comprises a lancecarriage 1. The lance carriage 1 has a mast 2 which stands upright alongthe Y axis and which is rotatable around the Y axis. The mast 2 has alance lifting stand 3 which is movable up and down in a verticaldirection, namely, along the Y axis. The lance lifting stand 3 is movedup and down along the mast 2 by a driving unit 4 comprising a hoistwhich is mounted at the top of the mast 2 and which uses a wire or achain.

A lance support platform 5 is attached to the lance lifting stand 3through a tilting gear 6. The lance support platform 5 is provided witha fixed outer cylinder 7 having a rectangular cross section. The fixedouter cylinder 7 is fixed to the lance support platform 5 through asliding plate 8 slidable in an elongated direction of the lance supportplatform 5.

The lance tilting gear 6 is rotated in the clockwise or thecounterclockwise direction by a drive motor not shown in the figure sothat the fixed outer cylinder 7 is tilted and rotated around the Z axisas illustrated in FIG. 2.

Herein, the fixed outer cylinder 7 defines a lance axis at its centerand internally supports a first-stage lance 9 comprising a cylindricalmember having a rectangular section.

A rack 10 is fixed to an outer surface of the first-stage lance 9 in theaxial direction. The rack 10 is engaged with a pinion 11 formed on thefixed outer cylinder 7. The pinion 11 is rotated in the clockwise or thecounterclockwise direction by a drive motor not illustrated in thefigure so that the first-stage lance 9 is moved forward and backwardalong the lance axis of the fixed outer cylinder 7.

A second-stage lance 12 comprising a cylindrical member having arectangular section is assembled into the first-stage lance 9. Athird-stage lance 13 comprising a cylindrical member having arectangular section is assembled into the second-stage lance 12. A lancehead portion 14 is formed on a top end of the third-stage lance 13.

As illustrated in FIG. 4, the lance head portion 14 is provided with arepairing nozzle 14-1 for spraying (namely, for injecting) a repairingmaterial. The repairing nozzle 14-1 is supplied with air, oxygen, andthe repairing material through a plurality of flexible hoses 15 (onlyone being illustrated in FIG. 4). The flexible hoses 15 can be extendedand wound up by a winding mechanism 16 in response to extension andcontraction of the lance.

The fixed outer cylinder 7 is provided with a gear 17 for rotating thefirst-stage through the third-stage lances 9, 12, and 13 around thelance axis passing through the center of the fixed outer cylinder. Byrotating the gear 17 by a motor not illustrated in the figure, the fixedouter cylinder 7 is rotated around the lance axis as illustrated in FIG.3. In a condition where the fixed outer cylinder 7 is arranged so thatthe lance axis coincides with the X axis, namely, in a condition wherethe fixed outer cylinder 7 is horizontally kept, the fixed outercylinder 7 is rotated around the X axis.

A pair of bearing plates 18 are fixed to the sliding plate 8. The fixedouter cylinder 7 is arranged to pass through circular holes 18-1 formedin the bearing plates 18. A wide-range camera 19 for observation of acondition of an oven wall during repair work is mounted on the fixedouter cylinder 7. With an appropriate countermeasure against heat, thewide-range camera 19 can be arranged at any desired position such as thetop end of the second-stage lance 12.

On the other hand, the mast 2 is attached onto the lance carriage 1through a swinging mechanism 20 to be swingable around the Y axis. Anoperation room 21 is located on the lance carriage 1 for manipulation ofthe multi-stage telescopic lance unit.

In this embodiment, a caterpillar system is adopted as a running systemof the lance carriage 1. However, since a rail for a coke guide car islaid on a coke side of the coke oven, a carriage may run on the railinstead of the caterpillar type of the carriage and the parts above theswinging mechanism 20 may be exchangeable.

Referring to FIG. 4, the lance head portion 14 is provided with a nozzlehead 22 having branched spraying ports 22-1 mounted on top ends of aplurality of the flexible hoses 15. A repairing nozzle 14-1 is connectedto one of the spraying ports 22-1 of the nozzle head 22 while a closingplug 22-3 is removably attached to each of the remaining spraying ports22-1. The repairing nozzle 14-1 opens towards a side surface of thelance head portion 14.

Openings 14-2 and 14-3 are formed in the side surface of the lance headportion 14 to be adjacent to the repairing nozzle 14-1. Within the lancehead portion 14, a CCD camera 23 and a radiation thermometer 24 arearranged opposite to the opening 14-2 while a laser range finder 25 formeasuring a distance to the oven wall surface is arranged opposite tothe opening 14-3. The lance head portion 14 is connected to a compressedcooling air supply pipe 26.

Through slits not shown in the figure but formed at attaching portionsof glass plates 14-4 and 14-5 shielding the openings 14-2 and 14-3,respectively, compressed cooling air blown into the lance head portion14 is spouted to outer surfaces of the glass plates.

A rotary disk 27 rotated by a motor 28 is located in front of the CCDcamera 23.

Referring to FIG. 5 in addition to FIG. 4, the rotary disk 27 isprovided with a plurality of bandpass filters F1 through F4equiangularly spaced for shielding and adjusting a light amount and aluminance to be supplied to the CCD camera 23. In correspondence to thecondition of the oven wall surface, exposure of the CCD camera 23 isadjusted and the bandpass filters F1 through F4 are switched toselectively pass wavelengths of light from the oven wall. In thismanner, those wavelengths of light emitted from the spraying flame arecut off to enable accurate observation of the flame spraying conditionof the repairing material.

The laser range finder 25 is for measuring a distance between the topend of the lance and the oven wall surface as well as a depth of a wornor a damaged area in order to quantitatively detect a wear condition ofthe oven wall as a wear amount. In other words, if a depression due towear is present in the oven wall, the size and the depth of thedepression are detected by measurement data obtained by the laser rangefinder 25.

An image of the oven wall surface picked up by the CCD camera 23, atemperature of the oven wall measured by the radiation thermometer 24,and the measurement data obtained by the laser range finder 25 aretransmitted from the lance head portion 14 through transmission paths30, 31, and 32, respectively, and then pass through the first-stagethrough the third-stage lances 9, 12, and 13, the inside of the fixedouter cylinder 7, and the winding mechanism 16 to be taken out andintroduced into the operation room 21.

The nozzle head 22 is supplied with the repairing material through theflexible hose 15. The flexible hose 15 is extended from the lance headportion 14 through the first-stage to the third-stage lances 9, 12, and13, the inside of the fixed outer cylinder 7, and the winding mechanism16 to be taken out and connected to a repairing material supplyingmechanism (not shown).

The above-mentioned multi-stage telescopic lance unit carries out repairby desiredly moving the lance head portion 14 along an oven wall 101 ina coke oven chamber 100 as illustrated in FIGS. 2 and 3 and by sprayingthe repairing material onto the damaged area of the oven wall 101. Aswill be understood from the above, it is sufficient that, during therepair work, the lance head portion 14 is moved along the oven wall 101in a linear fashion or a two-dimensional fashion. Accordingly, at leastby making the lance head portion 14 be tilted and rotated around the Zaxis and be extended and contracted along the lance axis during repair,it is possible to repair the worn or the damaged area of the oven wall101. In this event, up-and-down movement along the Y axis isunnecessary.

Referring to FIG. 6, description will be made as regards a firstembodiment of the multistage telescopic lance unit. A first wire 41 isfor forwardly moving the second-stage lance 12. The first wire 41 hasone end fixed to a rear end of the fixed outer cylinder 7 and the otherend fixed to a rear end of the second-stage lance 12 after being hungaround a first wheel 42 fixed to a front end of the first-stage lance 9.

A second wire 43 is for forwardly moving the third-stage lance 13. Thesecond wire 43 has one end fixed to a rear end of the first-stage lance9 and the other end fixed to a rear end of the third-stage lance 13after being hung around a second wheel 44 fixed to a front end of thesecond-stage lance 12.

A driving mechanism for forwardly moving the second-stage lance 12 andthe third-stage lance 13 is as follows. When the pinion 11 is rotated bythe drive motor not shown in the figure to advance the first-stage lance9, the second-stage lance 12 is moved forward by the first wire 41 andthe first wheel 42. In cooperation, the third-stage lance 13 is advancedby the second wire 43 and the second wheel 44 over the same distance.

A third wire 45 is for backwardly moving the second-stage lance 12. Thethird wire 45 has one end fixed to a front end of the fixed outercylinder 7 and the other end fixed to the rear end of the second-stagelance 12 after being hung around a third wheel 46 fixed to the rear endof the first-stage lance 9.

A fourth wire 47 is for backwardly moving the third-stage lance 13. Thefourth wire 47 has one end fixed to the front end of the first-stagelance 9 and the other end fixed to the rear end of the third-stage lance13 after being hung around a fourth wheel 48 fixed to the rear end ofthe second-stage lance 12.

Backward movement of the second-stage lance 12 and the third-stage lance13 is carried out in the manner which will presently be described. Thepinion 11 is rotated by the above-mentioned drive motor not illustratedin the figure to withdraw the first-stage lance 9. In this event, thesecond-stage lance 12 is withdrawn by the third wire 45 and the thirdwheel 46. In cooperation, the third-stage lance 13 is moved backward bythe fourth wire 47 and the fourth wheel 48.

Referring to FIG. 7, description will proceed to a movement guidemechanism of the multistage telescopic lance unit. In order to smooththe relative movement between the fixed outer cylinder 7 and thefirst-stage lance 9, between the first-stage lance 9 and thesecond-stage lance 12, and between the second-stage lance 12 and thethird-stage lance 13, first through sixth roller pairs 51a through 51cand 52a through 52c are provided. The first through the third rollerpairs 51a, 51b, and 51c are fixed to left and right opposite outersurfaces of the first-stage lance 9, the second-stage lance 12, and thethird-stage lance 13, respectively, at the rear ends thereof. The fourththrough the sixth roller pairs 52a, 52b, and 52c are fixed to left andright opposite inner surfaces of the fixed outer cylinder 7, thefirst-stage lance 9, and the second-stage lance 12, respectively, at thefront ends thereof.

Referring to FIG. 8, the second-stage and the third-stage lances 12 and13 comprise double cylindrical members 12a, 12b and 13a, 13b,respectively, having a rectangular cross section. Gaps are definedbetween the cylindrical members 12a and 12b and between 13a and 13b andare divided by a plurality of partitioning members 12c and 13c,respectively, extending along the lance center axis to form a pluralityof cooling water flow paths. Thus, a water-cooling jacket structure isachieved. Although the first-stage lance and the fixed outer cylinder 7are not illustrated in FIG. 8, such structure is also applied to thefirst-stage lance 9. Cooling water is supplied and discharged throughflexible hoses individually to and from the first-stage through thethird-stage lances 9, 12, and 13.

Turning back to FIG. 4, the lance head portion 14 coupled to the top endof the third-stage lance 13 comprises double cylindrical members 14a and14b, like the above-mentioned water-cooling jacket structure. Coolingwater flow paths are formed in a gap defined therebetween to achieveanother water-cooling jacket structure. In this connection, apredetermined number of cooling water passage holes 55 are formed at acoupling surface between the third-stage lance 13 and the lance headportion 14. In such a water-cooling jacket structure, cooling water issupplied through a part of a plurality of the cooling water flow paths,for example, through the flow paths formed, among top, bottom, leftside, and right side surfaces, at the top and the bottom surfaces whilethe cooling water is discharged through the flow paths formed at theleft and the right side surfaces. With this structure, it is possible toprevent the lance from being deformed due to drift of the cooling water.

In FIG. 8, the first-stage through the third-stage lances 9, 12, and 13and the fixed outer cylinder 7 comprise the cylindrical members having arectangular section. However, as illustrated in FIG. 9, use may be madeof double cylindrical members 61a, 61b and 62a, 62b having a hexagonalsection. In this event, four rollers 63c are arranged in left and rightspaces, four in number, defined between an inner surface of the innercylindrical member 61b of the second-stage lance and an outer surface ofthe outer cylindrical member 62a of the third-stage lance. A pluralityof partitioning portions 61c and 62c extending along the center axis areformed between the double cylindrical members 61a and 61b and betweenthe double cylindrical members 62a and 62b, respectively.

Referring to FIG. 10, the first-stage and the second-stage lances 9 and12 comprise double cylindrical members 71a, 71b and 72a, 72b having anoctagonal cross section, respectively. The third-stage lance 13comprises triple cylindrical members 73a, 73b, and 73c having a circularcross section. In this case also, four rollers 74 are arranged in aspace defined between an inner surface of the inner cylindrical member71b of the first-stage lance and an outer surface of the outercylindrical member 72a of the second-stage lance. Likewise, four rollers75 are arranged in a space defined between an inner surface of the innercylindrical member 72b of the second-stage lance and an outer surface ofthe outer cylindrical member 73a of the third-stage lance. Thearrangement of the rollers 74 and 75 are asymmetrical, for example,three at a lower portion and one at an upper portion. This arrangementis selected taking the weight of the lance into consideration and givesno influence upon extension and contraction of each stage. A pluralityof partitioning portions 77 and 78 extending along the center axis areformed between the double cylindrical members 71a and 71b and betweenthe double cylindrical members 72a and 72b, respectively.

Referring to FIGS. 11 and 12, description will be made as regardspositioning of the multistage telescopic lance unit. Generally, a pairof buckstays 58 are arranged at an entrance of the coke oven. Takingthis into consideration, stroke cylinders 56 and 57 are formed on bothsides of the lance support platform 5 at positions corresponding to thebuckstays 58.

The stroke cylinders 56 and 57 are for measuring distances La and Lbbetween the lance support platform 5 and the buckstays 58 so as toposition the lance support platform 5 in parallel to the buckstays 58.On the other hand, a reflector plate 59 (FIG. 12) is arranged at apredetermined level of the buckstays 58. The laser range finder 25 (FIG.4) contained in the lance head portion 14 of the multistage telescopiclance unit measures a distance between the reflector plate 59 and thelance head portion 14 so as to position the center of the multistagetelescopic lance unit at the center of the coke oven chamber 100 in awidthwise direction.

Referring to FIG. 13, description will proceed to a positioningoperation of the multistage telescopic lance unit. It is assumed herethat the oven wall 101 of the coke oven chamber 100 in the coke oven isobserved or the damaged area of the oven wall 101 is repaired. In thisevent, an operator in the operation room 21 at first makes the lancecarriage 1 run and move to a position in front of a furnace, namely, acoke oven of the coke oven chamber 100 to be observed or repaired.Subsequently, the stroke cylinders 56 and 57 are operated to be broughtinto contact with the buckstays 58 and 58 (step S1). Distances La and Lbare read (step S2). In a step S3, calculation is made of a swingingangle of the lance support platform 5 to swing the lance supportplatform 5 (step S4). In a step S5, judgement is made whether or not thedistances La and Lb are not greater than a predetermined value λ. Whenit is detected as a result of judgement that they are not greater thanthe predetermined value λ, the stroke cylinders 56 and 57 are withdrawn(step S6). Then, parallel positioning between the lance support platform5 and the coke oven is completed.

Referring to FIG. 14 in addition to FIG. 12, in a step S11, the pinion11 is rotated by driving the motor not shown in the figure to therebyextend the multistage telescopic lance unit through the rack 10. Thelaser range finder 25 contained in the lance head portion 14 is locatedat a position opposite to the reflector plate 59 (step S12).Subsequently, a distance Lc between the laser range finder 25 and thereflector plate is read (step S13). A travelling distance Lz of thelance support platform 5 along the Z axis is calculated in accordancewith the following equation (step S14).

    L=R-(Lz+Lc)

Herein, R and Lz represents a distance between the oven wall surface andthe oven center and a distance between a center line of the multistagetelescopic lance unit and the laser range finder 25, respectively.

In a step S15, the lance support platform 5 is moved along the Z axis.The operation proceeds to a step S16 to judge whether or not thedistance Lz is not greater than a predetermined allowance Lk. When it isdetected as a result of judgement that the distance Lz is not greaterthan the predetermined allowance Lk, positioning of the multistagetelescopic lance unit at the center of the the oven is completed. Now,the position of the top end of the lance before extension is set as areference point (0, 0, 0) on the X, Y, and Z axes.

Subsequently, the pinion 11 is rotated by driving the motor not shown inthe figure to extend, through the rack 10, the multistage telescopiclance unit which is thereby inserted to a predetermined position in thecoke oven chamber 100. The multistage telescopic lance unit scans theoven wall to be repaired. The CCD camera 23 contained in the lance headportion 14 picks up a condition of the oven wall as an image of the ovenwall to be displayed on a repair monitor which will later be described.The repair monitor displays a wearing status image along the X and the Yaxes at a coordinate corresponding to the travelling distances of arepairing material spraying position at the top end of the lance alongthe X, the Y, and the Z axes from the reference point (0, 0, 0) on theX, the Y, and the Z axes. With respect to the reference point (0, 0, 0)on the X, the Y, and the Z axes as a start point, an absolute positionof the repairing material spraying position is calculated from drivingamount information supplied from a lance driving system, which willlater be described, to a signal processing control section in theoperation room 21 and is corrected by an estimated flexure of the topend of the lance.

Next, supplied with wear amount data of the oven wall from the laserrange finder 25 and with position coordinate data of the depression inthe oven wall resulting from wear, the signal processing control sectioncarries out image processing and classifies each portion of the ovenwall by the level of wear, namely, the depth of the depression todisplay a wear distribution chart on the repair monitor.

With reference to observation data of the wear distribution chart andthe display of the monitor, the operator indicates a required repairrange of the oven wall surface and enters selection of a predeterminedrepair pattern to the signal processing control section. As a result, acontrol signal is delivered to the lance driving system in accordancewith the predetermined repair pattern. The lance driving system isresponsive to the control signal and controls the multistage telescopiclance unit to carry out automatic repair.

The first-stage through the third-stage lances 9, 12, and 13 and thelance head portion 14 of the multistage telescopic lance unit have thewater-cooled structure. Compressed cooling air is blown from thecompressed cooling air supply pipe 26 into the lance head portion 14containing the CCD camera 23, the radiation thermometer 24, the laserrange finder 25, the rotary disk 27 with the light shielding bandpassfilters, and the motor 28. The compressed cooling air is spouted throughthe slits formed at the attaching portions of the glass plates 14-4 and14-5 attached to the openings 14-2 and 14-3, respectively, to the outersurfaces of the glass plates. Thus, the spraying material is preventedfrom depositing to the outer surfaces of the glass plates 14-4 and 14-4due to rebounding.

In dependence upon the condition of the wall surface, selection is madeof one of the bandpass filters F1 through F4 of the rotary disk 27formed in front of the CCD camera 23 and rotated by the motor 28. Byadjusting exposure of the CCD camera 23 and by selectively transmittingthe wavelengths of light from the oven wall through the shielding filterthus selected, the wavelengths of light emitted from the spraying flameare cut off. It is therefore possible to observe the flame sprayingcondition of the repairing material. The lance head portion 14 can beremoved from the third-stage lance 13. On the other hand, the nozzlehead 22 contained in the lance head portion 14 has a plurality of thebranched spraying ports 22-1 as described in the foregoing. With thisstructure, it is possible to observe and repair left side and right sideoven walls 101 and a ceiling by changing an attaching position of therepairing nozzle 14-1 as illustrated in FIGS. 15(a)-15(c).

Specifically, FIG. 15(a) shows the attaching position of the repairingnozzle 14-1 in case where the right side oven wall 101-1 is observed andrepaired. FIG. 15(b) shows the attaching position of the repairingnozzle 14-1 in case where the left side oven wall 101-2 is observed andrepaired.

On the other hand, FIG. 15(c) shows the attaching position of therepairing nozzle 14-1 in case where the ceiling oven wall 101-3 isobserved and repaired.

In the multistage telescopic lance unit of the repairing apparatusaccording to this invention, the travelling distance of the first-stagelance 9 is equal to those of the second-stage lance 12 and thethird-stage lance 13. Accordingly, it is easy to calculate the positionof the repairing nozzle 14-1 of the lance head portion 14 at the top endof the lance. Furthermore, since the multistage telescopic lance unithas a polygonal section, the rotation of the fixed outer cylinder 7around the axis is reliably transmitted to the first-stage through thethird-stage lances 9, 12, and 13 and the lance head portion 14.

Referring to FIGS. 16 through 20, description will now proceed to arepairing method by the use of the above-mentioned multistage telescopiclance unit.

Referring to FIG. 16, the operation room 21 (FIG. 1) is equipped withthe repair monitor 34 for use in repairing a wall surface, the signalprocessing control section 35 for image processing of a wear amount, agraphic panel (not shown) for displaying a processed image, othermeasuring units, and a console.

The signal processing control section 35 is implemented by a computerand has at least the following functions as will presently become clear.Specifically, the signal processing control section 35 has the functionsof a worn area position coordinate calculating part 35-1 for calculatinga position coordinate of a worn area, a wear amount data calculatingpart 35-2 for calculating the wear amount, a worn area chart preparingpart 35-3 for preparing a worn area chart, a repair range and patterndetermining part 35-4 for determining a repair range and a repairpattern, a lance control part 35-5, and a flexure calculating part 35-6for calculating a flexure of the top end of the lance. An image pickedup by the wide range camera 19 (FIG. 1) mounted on the fixed outercylinder 7 (FIG. 1) is displayed on a wide range monitor 37. Theillustrated signal processing device 35 further comprises a memory 35-7storing a program for controlling the above-mentioned parts, and anothermemory 35-8 which will later be described.

Each drive portion in the multistage telescopic lance unit is controlledby a lance driving system 38 using a servo motor or the like.Specifically, the lance driving system 38 controls a position and avelocity of each drive portion, detecting an X-axis travelling amountLx, a Y-axis travelling amount Ly, a Z-axis travelling amount Lz, arotation angle R_(X), a swinging angle R_(Y), and a tilting angle R_(Z)illustrated in FIG. 1. The lance driving system delivers thoseinformation to the signal processing control section 35 in the operationroom 21. In addition to the above-mentioned functions, the signalprocessing control section 35 has a function of a multilayer neuralnetwork supplied with the X-axis travelling amount Lx, the Y-axistravelling amount Ly, and a rotation angle θ around the Z axis forproducing a flexure ε of the top end of the lance.

The multilayer neural network responds to the X-axis travelling amountLx, the Y-axis travelling amount Ly, and the rotation angle θ around theZ axis and produces an estimated value of the flexure ε of the top endof the lance from them. The position of the top end of the lance drivenby the lance driving system 38 is corrected by the use of the estimatedvalue.

The signal processing control section 35 is connected to the repairmonitor 34 for displaying the image of the wall surface supplied fromthe CCD camera 23 and to the wide range monitor 37 for displaying theimage supplied from the wide range camera 19.

In the above-mentioned structure, the signal processing control section35 is responsive to the signal supplied from the laser range finder 25and calculates the wear amount data of the oven wall surface. Inaddition, the signal processing control section is responsive to thedetection signal of the laser range finder 25 and the driving amount ofthe lance driving system 38 and calculates the position coordinate ofthe worn area of the oven wall with respect to the top end of the lance.

The signal processing control section 35 carries out image processing bythe use of the image information of the wall surface in the repairmonitor 34, the wear amount data, and the position coordinate data ofthe worn area and classifies each portion of the oven wall by the levelof wear to produce the wear distribution chart which is displayed on therepair monitor 34 or another graphic panel.

An operating section 39 is for the operator, who observes the weardistribution chart displayed on the repair monitor 34, to enterdesignation of the required repair range of the oven wall surface andthe repair pattern.

When the damaged area of the oven wall in the coke oven is repaired, theoperator at first operates the operating section 39 in the operationroom 21 to move the lance carriage 1 to the position in front of thecoke oven of the predetermined coke oven chamber. As described inconjunction with FIGS. 11 and 13, the lance carriage 1 is positioned ata predetermined location so that the distances between the buckstays 58on both sides and the lance support platform 5 are not greater than thepredetermined value.

Then, as described in conjunction with FIGS. 12 and 14, the fixed outercylinder 7 is moved along the Y axis and the Z axis through the slidingplate 8 so that the center of the lance is positioned at the center ofthe coke oven chamber. When the center of the lance is positioned at thecenter of the coke oven chamber as a result of the movement, theposition of the top end of the lance at that time instant beforeextension of the lance is set as a reference point (0, 0, 0) on the X,the Y, and the Z axes.

Once the reference point is set, the operator operates the lance drivingsystem 38 to insert the lance into the coke oven and to make the lancescan the oven wall to be repaired. The condition of the oven wall ispicked up by the CCD camera 23 at the top end of the lance, namely, inthe lance head portion. By this image pickup operation, an image of theoven wall in a restricted range (for example, 1 m by 1 m) is displayedon the repair monitor 34 as illustrated in FIG. 17. The display on therepair monitor 34 shows the wearing status image along the X and the Yaxes at the coordinate corresponding to the travelling distances of therepairing material spraying position at the top end of the lance alongthe X, the Y, and the Z axes with respect to the reference point (0, 0,0) on the X, the Y, and the Z axes.

The above-mentioned movement of the lance is performed by the lancedriving system 38. Driving amount information of each drive portion issupplied from the lance driving system 38 to the signal processingcontrol section 35. An absolute position of the repairing materialspraying position is calculated from the driving amount information withrespect to the reference point (0, 0, 0) on the X, the Y, and the Z axesas a start point and is corrected by estimation of the flexure ε of thetop end of the lance. The wide range monitor 37 displays an image of theoven wall in a relatively wide range as illustrated in FIG. 18.

Subsequently, the signal processing control section 35 carries out imageprocessing of the image information of the oven wall in the restrictedrange illustrated in FIG. 17, the wear amount data of the oven wallsupplied from the laser range finder 25, and the position coordinatedata of the depression in the oven wall resulting from wear. By thisimage processing, the signal processing control section 35 classifieseach portion of the oven wall by the level of wear, namely, the depth ofthe depression to make the wear distribution chart be displayed on therepair monitor 34, as illustrated in FIG. 19.

With reference to observation data of the wear distribution chart inFIG. 19, a temperature of the oven wall detected by the radiationthermometer 24, and the display on the monitor in FIG. 18, the operatoroperates the operating section 39 to indicate a required repair range ofthe oven wall surface and selects a predetermined repair pattern, asillustrated in FIG. 20. The signal processing control section 35 isresponsive to the repair pattern entered through the operating section39 and delivers a control signal to the lance driving system 38 tocontrol the lance driving system 38. Thus, automatic repair is carriedout by the multistage telescopic lance unit.

Referring to FIG. 20, the required repair range is represented by arectangle formed by connecting four points marked with crisscrosses. Therepair pattern is a pattern such that the repair range is scanned fromtop to bottom in a zigzag fashion. The repair pattern can be determinedas desired and may be selected from preselected ones or determined bymanual operation of the operator. During this repairing operation, theimage of the oven wall in a relatively wide range is picked up by thewide range camera 19 and displayed on the wide range monitor 37. It istherefore possible to confirm, from the outside of the oven, thecondition of repair work without any influence of dust, smoke, andhigh-temperature flame caused by spraying the repairing material.

When the lance does not reach the bottom of the oven even if the lancelifting stand 3 is moved down to a lowest level, the lance drivingsystem 38 is operated through the signal processing control section 35to carry out position control so that the lance extension length and thetilting angle R_(Z) are relatively varied by using a relationship of atrigonometric function. Thus, the top end of the lance can be made toapproach the bottom of the oven to carry out repair.

When the distance between the lance inserted into the oven and the wallsurface does not coincide with a selected distance, the lance drivingsystem 38 is operated through the signal processing control section 35in the similar manner as mentioned above to control the lance extensionlength and the swinging angle R_(Y) so that the distance between therepairing nozzle 14-1 and the oven wall surface is kept constant. As aconsequence, the worn area preliminarily detected can be automaticallyrepaired in accordance with any desired pattern.

Next referring to FIGS. 21 through 29, description will be made asregards an automatic repairing method according to a second embodiment.In this embodiment also, use is made of the multistage telescopic lanceunit having the structure illustrated in FIG. 16.

Referring to FIG. 21, the laser range finder 25 measures the distancebetween the top end of the lance and the wall surface in order toquantitatively detect the wear condition of the oven wall 101 as thewear amount data. Specifically, in presence of the depression in thewall surface resulting from wear, the size and the depth of thedepression can be obtained by the measurement data detected by the laserrange finder 25.

As described in conjunction with FIG. 16, the signal processing controlsection 35 is responsive to the signal supplied from the laser rangefinder 25 and calculates the wear amount data of the oven wall surface.In addition, the signal processing control section is responsive to thedriving amount data in the lance driving system 38 and calculates theposition coordinate of the worn area of the oven wall with respect tothe top end of the lance. The signal processing control section 35carries out image processing by the use of the image information of thewall surface in the repair monitor 34, the wear amount data, and theposition coordinate data of the worn area and classifies each portion ofthe oven wall by the level of wear to produce the wear distributionchart which is displayed on the repair monitor 34 or another graphicpanel.

As described above, the signal processing control section 35 has thememory 35-8. The memory 35-8 preliminarily memorizes, as basic motionpatterns for the repairing nozzle 14-1, a horizontal reciprocal motionpattern illustrated in FIG. 22(a), a vertical reciprocal motion patternillustrated in FIG. 22(b), a circular motion pattern illustrated in FIG.22(c), and a stop pattern illustrated in FIG. 22(d).

The memory 35-8 of the signal processing control section 35 furthermemorizes travelling patterns as illustrated in FIGS. 23(a)-23(f). Forexample, FIG. 23(a) shows a travelling pattern comprising a combinationof a horizontal movement and a vertical movement within the repairrange. On the other hand, FIG. 23(b) shows a travelling patterncomprising a combination of the vertical movement and the horizontalmovement. FIG. 23(c) shows a spiral travelling pattern comprising acombination of the vertical movement and the horizontal movement fromthe outside to the inside. FIG. 23(d) shows another spiral travellingpattern comprising a combination of the vertical movement and thehorizontal movement from the inside to the outside. FIG. 23(e) showsanother spiral travelling pattern from the outside to the inside. FIG.23(f) shows another spiral travelling pattern from the inside to theoutside. Such travelling patterns can readily be achieved by the use ofthe multistage telescopic lance unit capable of executing theabove-mentioned motions with respect to the X, the Y, and the Z axes.

In order to carry out repair, the operator operates the operatingsection 39 in the operation room 21 to move the lance carriage 1 to theposition in front of the oven of the predetermined coke oven chamber.

Then, as described in conjunction with FIGS. 11 and 13, the lancesupport platform 5 is positioned at the predetermined location so thatthe distances between the buckstays 58 on both sides and the lancesupport platform 5 are not greater than the predetermined value.Subsequently, as described in conjunction with FIGS. 12 and 14, thefixed outer cylinder 7 is moved along the Z axis through the slidingplate 8 so that the center of the lance is positioned at the center ofthe coke oven chamber. The position of the top end of the lance beforeextension and at the time instant when the center of the lance ispositioned at the center of the coke oven chamber is set as a referencepoint (0, 0, 0) on the X, the Y, and the Z axes.

Subsequently, the operator operates the lance driving system 38 throughthe signal processing control section 35 to insert the lance into thecoke oven and to make the lance scan the oven wall to be repaired. Thecondition of the oven wall is picked up by the CCD camera 23 at the topend of the lance to obtain the image of the oven wall. The image thuspicked up is displayed on the repair monitor 34. The repair monitor 34displays the wearing status image along the X and the Y axes in thecoordinate corresponding to the travelling distances of the repairingmaterial spraying position at the top end of the lance along the X, theY, and the Z axes with respect to the reference point (0, 0, 0) on theX, the Y, and the Z axes.

The movement of the lance is performed by the lance driving system 38under control of the signal processing control section 35 in the mannersimilar to the above-described embodiment. The driving amountinformation of each drive portion is supplied from the lance drivingsystem 38 to the signal processing control section 35. The absoluteposition of the repairing material spraying position is calculated fromthe driving amount information with respect to the reference point (0,0, 0) on the X, the Y, and the Z axes as a start point and is correctedby estimation of the flexure ε of the top end of the lance.

Subsequently, the signal processing control section 35 carries out imageprocessing of the driving amount information supplied from the lancedriving system 38, the wear amount data of the oven wall supplied fromthe laser range finder 25, and the position coordinate data of thedepression in the oven wall resulting from wear. The signal processingcontrol section classifies each portion of the oven wall by the level ofwear, namely, the depth of the depression to make the wear distributionchart as illustrated in FIG. 19 be displayed on the repair monitor 34.

With reference to the observation data of the wear distribution chart asdisplayed, the display on the monitor, and the temperature of the wallsurface at the worn area as detected by the radiation thermometer 24,the operator confirms the shape and the range of the damage and, independence upon the shape and the range of the damage at a site to berepaired, carries out selection and combination of the basic motionpatterns and the travelling patterns illustrated in FIGS. 22 and 23. Theoperator supplies the lance driving system 38 with indication of therequired repair range within the oven wall surface and a selected one ofthe predetermined repair patterns.

The signal processing control section 35 is responsive to the indicatedrepair range and the selected one of the predetermined repair patternsand delivers the control signal to the lance driving system 38 tocontrol the travelling speed of the repairing nozzle 14-1 and/or theamount of the repairing material to be injected. Thus, automatic repairis carried out by the multistage telescopic lance unit.

FIG. 24 shows an example of the selected repair pattern in case wherethe oven wall is repaired by flame spraying in accordance with theabove-mentioned method. In this case, the repair range is relatively aslarge as about 1 m². In this connection, the circular motion patternillustrated in FIG. 22(c) is selected as the basic motion pattern forthe repairing nozzle 14-1. On the other hand, a combination of thehorizontal movement pattern and the vertical movement patternillustrated in FIG. 23(a) is selected as the travelling pattern. Inaccordance with the selected travelling pattern, the signal processingcontrol section 35 controls the lance driving system 38 to position therepairing nozzle 14-1 at an upper left corner of the damaged area. Therepairing nozzle 14-1 individually repeats the circular motion at thatposition. Then, the center of the circular motion is moved leftward,rightward, upward, and downward in accordance with the selectedtravelling pattern.

The diameter and the rotation speed of the circular motion are differentin dependence upon a flame spraying method, characteristics of amechanical device, and so on. In this embodiment, it is assumed that thediameter is equal to 50 mmφ and the rotation speed is equal to 20mm/sec. The travelling speed of the center of the circular motion ispreferably equal to the rotation speed. As to the travelling direction,it is desirable that the horizontal direction is given priority. Afterthe center of the circular motion is moved in the horizontal directionfor a predetermined distance (about 70 cm in this embodiment), thecenter is moved downwards (moved down by about 40 mm in this embodiment)so that successive circular motions are partially overlapped with eachother. Again, movement in the horizontal direction is carried out. Theabove-mentioned operation is repeated to automatically repair the frontsurface of the damaged area.

Referring to FIGS. 25(a)-25(c), description will be made as regards anoperation in case where the damaged area having a relatively shallowdamage is repaired by a single flame spraying operation. Incorrespondence to a damage depth D1 illustrated in FIG. 25(a), thetravelling speed of the repairing nozzle 14-1 is varied as illustratedin FIG. 25(c) to control a spraying thickness. In this manner, thedamaged area can be repaired by the single flame spraying operation. Asregards the travelling pattern, the travelling pattern illustrated inFIG. 23(a) is selected for the range illustrated in FIG. 25(b).

Referring to FIGS. 26(a)-26(c), description will be made as regardsanother operation in case where the damaged area having a relativelyshallow damage is repaired by a single flame spraying operation. Incorrespondence to the damage depth D1 illustrated in FIG. 26(a), theamount of the spraying material to be injected from the repairing nozzle14-1 is varied as illustrated in FIG. 26(c) to control the sprayingthickness. In this manner, the damaged area can be repaired by thesingle flame spraying operation. As regards the travelling pattern, thetravelling pattern similar to that illustrated in FIG. 25(b) isselected.

Referring to FIGS. 27(a)-27(c), description will be made as regards anoperation in case where a deep damaged area is repaired in the orderfrom a deepest level to a shallow level. As illustrated in FIGS. 27(a)and (b), a repair range Ar is divided into a plurality of segments alongthe depth of the damage. Herein, it is divided into first through thirdsegments Ar-1 through Ar-3. In this case, as illustrated in FIG. 27(c),the first through the third segments Ar-1, Ar-2, and Ar-3 are repairedin this order from the deepest level. The repair range is varied at eachof the first through the third segments Ar-1, Ar-2, and Ar-3. In thisrepair pattern, a surface plane is contoured at each stage of repair. Itis therefore possible to prevent plethoric deposition of the repairingmaterial and to smooth a boundary to a brick surface free from damage.Such a plethoric deposition can readily be prevented by monitoring thedistance to the repair surface by the use of the laser range finder 25.

In the above-mentioned automatic repair of the damaged area, it isimportant to keep a distance Lm between the oven wall 101 and therepairing nozzle 14-1 and the temperature of the oven wall 101 constantin order to improve adhesive strength of the spraying material anddurability of the spraying material. For this purpose, the signalprocessing control section 35 is successively supplied from the laserrange finder 25 with the distance Lm between the repairing nozzle 14-1and the wall surface, as illustrated in FIG. 28, and controls the lancedriving system 38 to control the lance extension length and the swingingangle R_(Y). Through such control, the distance Lm between the repairingnozzle 14-1 and the oven wall 101 is kept constant. In response to thetemperature of the oven wall 101 successively supplied from theradiation thermometer 24, the signal processing control section 35controls the travelling speed of the repairing nozzle 14-1 and/or theamount of the spraying material to be injected so as to keep thetemperature of the repair surface constant.

It is assumed that, during execution of automatic repair in accordancewith the repair pattern as selected, temporary interruption of theautomatic repair and temporary retreat of the lance carriage 1 arerequired due to interference with a pushing machine of the coke oven ora coke guide car. In this event, the following operation is carried out.The multistage telescopic lance unit is shortened to move the repairingnozzle 14-1 as desired. Thereafter, the lance carriage 1 is temporarilyretreated. At the time instant when the interference with the pushingmachine or the coke guide car is released, the lance carriage 1 is againlocated at a former position before retreat. Then, as illustrated inFIG. 29, the multistage telescopic lance unit is extended and therepairing nozzle 14-1 is located at a position Pj at the time ofinterruption. The automatic repair is continued from the position at thetime of interruption until a completion position Pk is reached.

Turning back to FIG. 21, the lance is inserted substantially in parallelto the oven wall 101. The laser range finder 25 measures distancesZ_(T1) and Z_(T2) from the oven wall surface 101 at given positions P₁and P₂ in normal brick areas between which the damaged area isinterposed. The distances are memorized in the memory of the signalprocessing control section 35. In order to keep an appropriate distancebetween the oven wall 101 and the repairing nozzle 14-1 during repair byflame spraying, a distance Z₁ between the measurement position and anapproaching position nearer to the oven wall 101 is continuouslycalculated from the length from a swinging center of the lance to therepairing nozzle 14-1 and the travelling speed. When the distance Z₁ ina zone between the positions P₁ and P₂ and a measured distance Z2 has arelationship Z₁ +Z₂ ≦Z_(T1) (or Z_(T2)), an alarm is produced. Thus, itis possible to warn the operator against plethoric deposition.

In the foregoing embodiments, description has been directed to the caseswhere the repair pattern as illustrated in FIG. 24 is selected which isa combination of the basic motion pattern and the travelling pattern.However, it is possible, by the use of one of the basic motion patternand the travelling pattern alone, to repair the oven wall in a dottedfashion or in a linear fashion to the depth of the worn area as detectedby the laser range finder. Accordingly, it is possible to repair onepoint alone by the use of the repairing method according to thisinvention. Description has been made as regards the case where the weardistribution chart of the worn area is prepared by the use of the imagepickup device and the monitor and through image processing of the imageinformation of the wall surface. However, it is also possible to preparethe wear distribution chart of the worn area by the use of the positioncoordinate data of the worn area and the wear amount data measured bythe laser range finder alone. Furthermore, it is possible to select anddetermine the basic motion pattern and/or the travelling pattern inaccordance with the wear distribution chart thus obtained.

Description has been made as regards the case where either thetravelling speed of the repairing nozzle or the amount of the repairingmaterial to be sprayed (namely, the amount to be injected) is controlledduring repair. However, the worn area may be repaired by controllingboth the travelling speed of the repairing nozzle and the amount of therepairing material to be sprayed. Description has been made as regardsthe case where the laser range finder continuously monitors, while theoven wall is repaired, that the repair surface varying from time to timeexceeds the virtual line of the normal oven wall surface. However, it isalso possible, by watching the amount of the repairing material to besprayed or the repair time, to monitor that the repair surface exceedsthe virtual line of the normal oven wall surface. Furthermore, when itis detected that the repair surface exceeds the virtual line of thenormal oven wall surface, not only the alarm but also an instruction tostop the injection of the repairing material are produced so that theinjection of the repairing material is stopped.

In the foregoing embodiments, the laser range finder is used as thedistance sensor. However, it will readily be understood that anultrasonic sensor may be used. Description has been made as regards thecase where the image pickup device comprises a single CCD camera mountedon the lance head portion. However, a plurality of the CCD cameras canbe mounted on the lance head portion to obtain a three-dimensionalimage. It is possible to prepare the wear distribution chart from thethree-dimensional image or to determine the repair range with referenceto the three-dimensional image.

Description has been made on the assumption that the repairing apparatusis movable up and down along the Y axis. However, inasmuch as therepairing apparatus can be rotated and tilted around the Z axis asillustrated in the figure, up-and-down movement along the Y axis is notessential. At any rate, it is sufficient that the oven wall repairingapparatus according to this invention has a lance capable of moving in alinear fashion or along a plane on the oven wall surface.

EFFECT OF THE INVENTION

With the oven wall repairing apparatus according to this invention, itis easy to control the position of the repairing nozzle. It is possibleto carry out observation, measurement, and repair over a wide rangewithin the oven simply by rearrangement of the lance head portion.Therefore, a repair work time is remarkably reduced. With the oven wallrepairing method according to this invention, repair work is carried outby selecting the repair range and the repair pattern based onquantitative detection of the wear condition and by automaticallyoperating the repairing lance. In addition, a smoothness is improved onthe boundary with the normal brick surface and on the repaired surface.Plethoric deposition is prevented to suppress an increase of push-outresistance when the coke is pushed out. In addition, the durability of arepaired area is improved.

INDUSTRIAL APPLICABILITY

As described above, the method and the apparatus for repairing a cokeoven according to this invention is capable of remarkably extending thelifetime of the coke oven by repairing the oven wall of the coke oven.

We claim:
 1. A coke oven repairing method for repairing an oven wall ofa coke oven by the use of a lance, said method comprising the steps ofarranging a distance sensor at a top end of said lance, successivelymeasuring a depth of a damaged area in an oven wall surface bysuccessively scanning the oven wall surface by a beam emitted from saiddistance sensor, determining an amount of a repairing material withreference to a measurement result obtained by said distance sensor, andinjecting the amount of the repairing material from a repairing nozzleto said damaged area to thereby repair said damaged area.
 2. A coke ovenrepairing method as claimed in claim 1, further comprising the steps ofmoving said distance sensor along said oven wall surface to obtainposition coordinate data of said worn area, and repairing said worn areawith reference to said position coordinate data and the depth of saidworn area.
 3. A coke oven repairing method as claimed in claim 2,further comprising the steps of determining a repair range on said ovenwall surface with reference to the measurement result obtained by saiddistance sensor and said position coordinate data, and moving saidrepairing nozzle within said repair range as determined to therebyrepair said worn area.
 4. A coke oven repairing method as claimed inclaim 3, further comprising the steps of preparing a plurality of repairpatterns, selecting, as a selected repair pattern, a particular one incorrespondence to said repair range as determined, and moving saidrepairing nozzle within said repair range in accordance with saidselected repair pattern to thereby repair said worn area.
 5. A coke ovenrepairing method as claimed in claim 3, further comprising the steps ofpreparing a plurality of basic motion patterns, and moving saidrepairing nozzle within said repair range in accordance with any one ofsaid basic motion patterns to thereby repair said worn area.
 6. A cokeoven repairing method as claimed in claim 3, further comprising thesteps of preparing a plurality of travelling patterns, and moving saidrepairing nozzle within said repair range in accordance with any one ofsaid travelling patterns to thereby repair said worn area.
 7. A cokeoven repairing method as claimed in claim 3, further comprising thesteps of preliminarily setting a plurality of travelling patterns ofsaid lance in correspondence to said repair range, and moving saidrepairing nozzle within said repair range in accordance with acombination of each travelling pattern and basic motion patterns tothereby repair said worn area.
 8. A coke oven repairing method asclaimed in any one of claims 1 through 7, further comprising the stepsof preparing a wear distribution chart of said worn area by the use ofsaid distance sensor, and repairing said worn area in accordance withsaid wear distribution chart.
 9. A coke oven repairing method as claimedin claim 8, further comprising the step of controlling a travellingspeed of said repairing nozzle and/or an amount of said repairingmaterial to be injected to thereby repair said worn area.
 10. A cokeoven repairing method as claimed in any one of claims 1 through 7,further comprising the step of controlling a travelling speed of saidrepairing nozzle and/or an amount of said repairing material to beinjected to thereby repair said worn area.
 11. A coke oven repairingmethod as claimed in claim 1, further comprising the step of monitoring,with reference to the measurement result of said distance sensor, that arepair surface varying from time to time exceeds a virtual line of anormal oven wall surface.
 12. A coke oven repairing method as claimed inclaim 11, further comprising the step of producing an alarm and/or aninstruction to stop injection of said repairing material when saidrepair surface exceeds the virtual line of said normal oven wallsurface.
 13. A coke oven repairing method as claimed in claim 12,further comprising the step of monitoring an amount of said repairingmaterial to be injected and/or a repair time to thereby detect that saidrepair surface exceeds the virtual line of said normal oven wallsurface.
 14. A coke oven repairing method as claimed in claim 1, furthercomprising the steps of setting a distance to a normal oven wall surfacesurrounding said worn area by the use of said distance sensor, measuringa distance between said distance sensor and a repair surface varyingfrom time to time during repair, and monitoring that said repair surfacevarying from time to time exceeds the virtual line of said normal ovenwall surface at said worn area.
 15. A coke oven repairing method asclaimed in claim 14, further comprising the step of producing an alarmand/or an instruction to stop injection of said repairing material whensaid repair surface exceeds the virtual line of said normal oven wallsurface.
 16. A coke oven repairing method as claimed in claim 15,further comprising the step of watching an amount of said repairingmaterial to be injected and/or a repair time to thereby detect that saidrepair surface exceeds the virtual line of said normal oven wallsurface.
 17. A coke oven repairing method for repairing an oven wall ofa coke oven by the use of a repairing apparatus capable of controlling aposition of a repairing nozzle, comprising the steps of preliminarilysetting, in a lance control section, basic motion patterns for saidrepairing nozzle and traveling patterns within a repair range, detectingwear information of a damaged area by scanning the damaged area of theoven wall by a distance detecting beam, determining said repair rangeprior to start of repair with reference to the wear information of thedamaged area, selecting a repair pattern for the damaged area comprisinga combination of one of said basic motion patterns for said repairingnozzle and one of said traveling patterns, and controlling at least oneof a traveling speed of said repairing nozzle and an amount of arepairing material to be injected to thereby repair said damaged area.18. A coke oven repairing method as claimed in claim 17, furthercomprising the steps of specifying said repair range with reference toimage information of said worn area, and obtaining wear information ofsaid repair range as specified.
 19. A coke oven repairing method asclaimed in claim 17, further comprising the steps of preparing a weardistribution chart with reference to wear information of said worn areato determine said repair range, selecting the repair pattern comprisinga combination of one of said basic motion patterns for said repairingnozzle and one of said travelling patterns, and controlling thetravelling speed of said repairing nozzle and/or the amount of saidrepairing material to be injected to thereby repair said worn area. 20.A coke oven repairing method as claimed in any one of claims 17 through19, further comprising the step of monitoring that a repair surfacevarying from time to time exceeds a virtual line of a normal oven wallsurface.
 21. A coke oven repairing method as claimed in claim 20,further comprising the step of producing an alarm and/or an instructionto stop injection of said repairing material when said repair surfacevarying from time to time exceeds the virtual line of said normal ovenwall surface.
 22. A coke oven repairing method as claimed in claim 20, adistance sensor being used to monitor that said repair surface exceedsthe virtual line of said normal oven wall surface.
 23. A coke ovenrepairing method comprising the steps of scanning an oven wall surfaceby the use of an image pickup device mounted at a top end of a lancehaving a repairing nozzle for injecting a repairing material, displayingan image on a monitor, successively scanning said oven wall surfacewhile measuring a distance between the top end of said lance and saidoven wall surface by a distance sensor mounted at the top end of saidlance to obtain wear amount data of said oven wall surface includinglocation, size and depth of a damaged area, calculating, from a drivingamount of a lance driving mechanism for driving said lance, positioncoordinate data of the damaged area in said oven wall surface withrespect to the top end of said lance, determining amount of repairingmaterial for a required repair range on said oven wall surface andselecting a repair pattern for movement of said lance over the damagedarea with reference to image information of said wall surface, said wearamount data, and said position coordinate data of said worn area, andrepairing said worn area in said oven wall surface by spraying inaccordance with the repair pattern selected.
 24. A coke oven repairingapparatus comprising a multistage telescopic lance unit provided at itstop end with a repairing nozzle which is for injecting a repairingmaterial and which is movable, a lance driving means for driving saidmultistage telescopic lance unit, a distance sensor mounted at the topend of said multistage telescopic lance unit for measuring distance froman oven wall surface, and a lance operating means for calculating wearamount data of said oven wall surface in response to a signal suppliedfrom said distance sensor and for operating said lance unit withreference to said wear amount data and position coordinate data of aworn or a damaged area so that said nozzle is moved over said worn areain said oven wall surface,said lance operating means comprising signalprocessing control means for calculating, from a driving amount of saidlance driving mechanism, position coordinate data of said worn ordamaged area in said oven wall surface with respect to the top end ofsaid lance and for determining location, size and depth of the damagedarea on said oven wall surface and selecting a repair pattern withreference to said position coordinate data of said worn or damaged areaand said wear amount data, said lance operating means being responsiveto instructions from said signal processing control means for operatingsaid lance so that said repairing nozzle is moved along said repairpattern over said worn or damaged area in said oven wall surface whilecontrolling at least one of a traveling speed for said repairing nozzleand an amount of repairing material to be injected onto said worn ordamaged area.
 25. A coke oven repairing apparatus as claimed in claim24, said repairing apparatus further comprising an image pickup devicemounted at the top end of said lance for picking up an image of saidoven wall surface, and a monitor for displaying said image of said ovenwall surface picked up by said image pickup device.
 26. A coke ovenrepairing apparatus as claimed in any one of claims 24 and 25, saidmultistage telescopic lance unit being movable along a plane(two-dimensionally), on a predefined X-Y-Z coordinate system, along atleast two axes with respect to said oven wall surface.
 27. A coke ovenrepairing apparatus as claimed in any one of claims 24 and 25, saidmultistage telescopic lance unit being extendable, movable, androtatable and tiltable around a Z axis.
 28. A coke oven repairingapparatus as claimed in claim 26, said multistage telescopic lance unitbeing rotatable around a lance axis and a Y axis.
 29. A coke ovenrepairing apparatus using a multistage telescopic lance unit, whereinsaid multistage telescopic lance unit has an axis extendable in apredetermined direction and a lance driving system for driving saidmultistage telescopic lance unit, said multistage telescopic lance unitcomprising a first-stage lance, second-stage through N-th-stage lancesassembled in said first-stage lance to be extendable in an axialdirection, and a fixed outer cylinder for fitting and accommodating saidfirst-stage lance therein to thereby support said first-stage throughsaid N-th-stage lances, said lance driving system comprising a lanceextension driving mechanism formed between said fixed outer cylinder andsaid first-stage through said N-th stage lances, and a tilting mechanismfor tilting said fixed outer cylinder in a vertical plane.
 30. A cokeoven repairing apparatus as claimed in claim 29, said lance extensiondriving mechanism comprising a rack fixed to an outer surface of saidfirst-stage lance, a pinion formed on said fixed outer cylinder, aforward movement mechanism for moving said second-stage through saidN-th-stage lances in cooperation with a forward movement of saidfirst-stage lance by said rack and said pinion, and a backward movementmechanism for moving said second-stage through said N-th-stage lances incooperation with a backward movement of said first-stage lance.
 31. Acoke oven repairing apparatus as claimed in claim 29 or 30, each of saidfirst-stage through said N-th stage lances having a cooling jacketstructure formed by multiple cylindrical members having partitioningportions extending in a longitudinal direction with a cooling mediumflowing therebetween.
 32. A coke oven repairing apparatus as claimed inclaim 29 or 30, said multistage telescopic lance unit comprising acylindrical member having a polygonal cross section.
 33. A coke ovenrepairing apparatus as claimed in claim 32, each of said first-stagethrough said N-th-stage lances having a cooling jacket structure formedby multiple cylindrical members having partitioning portions extendingin a longitudinal direction with a cooling medium flowing therebetween.34. A coke oven repairing apparatus as claimed in claim 29, said N-thstage lance having both a cooling jacket structure formed by multiplecylindrical members having partitioning portions extending in alongitudinal direction with a cooling medium flowing therebetween and astructure such that said cooling medium in an inner cylindrical memberis injected from a portion around a transparent window formed at the topend thereof.
 35. A coke oven repairing apparatus as claimed in claim 29,said lance driving system further comprising a swinging mechanism forswinging said fixed outer cylinder in a horizontal plane and a rotatingmechanism for rotating said fixed outer cylinder around a lance axis.36. A coke oven repairing apparatus as claimed in claim 29, saidN-th-stage lance being provided at its top end with a nozzle forinjecting a repairing material and a distance sensor for measuring adistance to said oven wall surface.